260 Important Refrigeration And Air Conditioning MCQ Question and Answer | PDF Free Download
1.The curved lines on a psychrometric chart indicates
- ADry bulb temperature
- BWet bulb temperature
- CDew point temperature
- DRelative humidity
2.In a reversed Brayton cycle, the heat is absorbed by the air during
- AIsentropic compression process
- BConstant pressure cooling process
- CIsentropic expansion process
- DConstant pressure expansion process
3.The wet bulb temperature at 100% relative humidity is ________ dry bulb temperature.
- ASame as
- BLower than
- CHigher than
- DNone of these
4.The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P.
- AMore
- BLess
- CEqually
- DUnpredictable
5.The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P.
- AMore
- BLess
- CEqually
- DUnpredictable
6.A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
- ALack of cooling water
- BWater temperature being high
- CDirty condenser surface
- DAll of these
7.In a psychrometric process, the sensible heat added is 30 kJ/s and the latent heat added is 20 kJ/s. The sensible heat factor for the process will be
- A0.3
- B0.6
- C0.67
- D1.5
8.The thermostatic expansion valve is used in ________ type of evaporators.
- AFlooded
- BDX coil
- CDry
- DNone of these
9.During heating and humidification, the final relative humidity of air
- ACan be lower or higher than that of the entering air
- BIs lower than that of the entering air
- CIs higher than that of the entering air
- DNone of the above
10.The capillary tube, as an expansion device, is used in
- ADomestic refrigerators
- BWater coolers
- CRoom air conditioners
- DAll of these
11.The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure, is called
- AHumidity ratio
- BRelative humidity
- CAbsolute humidity
- DDegree of saturation
12.The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure, is called
- AHumidity ratio
- BRelative humidity
- CAbsolute humidity
- DDegree of saturation
13.For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then
- ABigger cabinet should be used
- BSmaller cabinet should be used
- CPerfectly tight vapour seal should be used
- DRefrigerant with lower evaporation temperature should be used
14.Pick up the wrong statement. A refrigerant should have
- ATow specific heat of liquid
- BHigh boiling point
- CHigh latent heat of vaporization
- DHigher critical temperature
15.Relative humidity is given by (where pv = Partial pressure of water vapour, pb = Barometric pressure, ps = Pressure of saturated air, pd = Pressure at dry bulb temperature, pw = Saturation pressure corresponding to wet bulb temperature, and μ = Degree of saturation)
- A0.622 Pv / (Pb - Pv)
- Bμ/[1 - (1 - μ) (Ps/Pb)]
- C[Pv (Pb - Pd)]/ [Pd (Pb - Pv)]
- DNone of these
16.The emissivity of a polished silver body is _________ as compared to black body.
- ASame
- BLow
- CVery low
- DHigh
17.The human body feels comfortable when the heat stored in the body is
- APositive
- BNegative
- CZero
- DNone of these
18.In a refrigeration system, the expansion device is connected between the
- ACompressor and condenser
- BCondenser and receiver
- CReceiver and evaporator
- DEvaporator and compressor
19.For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is ________ that for counter flow.
- AEqual to
- BLess than
- CGreater than
- DNone of these
20.The specific humidity during heating and humidification process.
- ARemains constant
- BIncreases
- CDecreases
- DNone of these